Explicitly set locale fallbacks

With a recent change in i18n, default language is not
included in fallbacks by default. This causes that
MissingTranslationData exception is raised both in
development and production mode.

This patch sets explicitly fallbacks language to english
which assures that english is used for missing translations.

config/application.rb

@@ -66,6 +66,12 @@ module Gitlab
     # config.i18n.default_locale = :de
     config.i18n.enforce_available_locales = false
 
+    # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
+    # the I18n.default_locale when a translation can not be found).
+    # We have to explicitly set default locale since 1.1.0 - see:
+    # https://github.com/svenfuchs/i18n/pull/415
+    config.i18n.fallbacks = [:en]
+
     # Translation for AR attrs is not working well for POROs like WikiPage
     config.gettext_i18n_rails.use_for_active_record_attributes = false
 

config/environments/production.rb

@@ -65,10 +65,6 @@ Rails.application.configure do
   # Enable threaded mode
   # config.threadsafe! unless $rails_rake_task
 
-  # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
-  # the I18n.default_locale when a translation can not be found)
-  config.i18n.fallbacks = true
-
   # Send deprecation notices to registered listeners
   config.active_support.deprecation = :notify